Overheated Motor

One of the possibilities for the motor overheating is that the mechanical load exceeded what the motor was able to sustain, and the overload protection device was either incorrectly set, absent or failed to operate in some way.

ok thanks for that sir...what you mean is that the cause of the problem directly to the powerboard not the motor actually?

ok thanks.But actually the centrifuge have no leftlits or manual now.Can you give me idea sir what electronics part or components failed of the powerboard.

It's not visible from here.

If it exists, it will look a bit like this:

however, replacing something doesn't actually solve the issue as to why the motor was overloaded, which is a mechanical issue.

The equipment manufacturer has been involved in sorting this out, presumably?

yah, thanks for that I email now the company which is the hettich.Actually I'm also troubleshooter of the laptop.I'm actually performing the works of the biotech as my other works preparably electronics and biotech.I encountered this problem but compare to the image you posted its really not I could not saw burn parts.Actually its very hard to dismantle the powerboard inside because of the twin boards soldered parallel using a wire.

So, what about the mechanical load? - torque presented times angular velocity - that sort of thing?

• Is the rotor larger and presenting more air resistance?
• Is there too much stuff in the rotor containers?
• Is there some other form of drag that is outside the design parameters and causing the motor to operate outside its load envelope?
• Why is there no overload protection device in the control circuit?
• Etc.

Actually I dont put any capilliaries or spacer inside the rotor actually blank.I run it just as testing to sustain the unit if its capable to carry out to rcf

You haven't defined overheating in the question, some motors run hot but they are within specification. What is the motor temperature, is it still working, did it actually burn out? You haven't mentioned the cooling arrangements, I have seen motors overheat where the cooling impeller was slipping on the shaft and not delivering enough cooling air. In any motor less than 100% efficient there will be waste heat, how is this dealt with?

yah! I just found now the manual I just read it but I dont read max temp application.There are no cooling or exhaust fan inside.But as I experience in computer processor heat resistance compare to the motor that not usual as I just feel using my hand.When it got to max speed If I'm not forgot has a error code display u 9 or u 2.

Centrifuge? Stuxnet maybe?

Hemacrit actually sir 15000 rpm

Have you checked the motor bearings?

Ok, I'm going to assume that this is an existing, successful centrifuge design that has now failed by overheating after a reasonable period of good operation. My first idea is that the cooling air movement has been blocked now or in the past by some debris that has reduced the self cooling capability. This in turn has broken down the insulation of the motor wiring so that a partial short has happened. This partial short causes more than the designed current to flow through the motor so more heat is produced while less cooling exists. Now there is also the possibility that just the age of the motor windings has caused this insulation breakdown to produce more heat in the motor windings than the self cooling can handle.

Yah, that also my suspect sir of the trouble.This hemacrit actually is old.I cannot remove the board cause its twin board soldered in parallel with a thin wires its very difficult to remove.I cannot check the load resistor and load capacitor temp detector line in power board.

Take a look at the bearing. At that speed, you have to make sure the bearing is at tip top condition all the time!

thanks for that sir, I just check it I found on the buttom a corrosion

In some cases it's true that the motor could be overloaded for the actual design, which is only a theory. However: I believe that most product machinery designs are correct, but is worth looking into. By due process of elimination of the first theory, I would then look at the installation and it's atmosphere of conditions, such as: adequate ventilation and surrounding equipment, which will raise the element of heat tramendously. Before you do that, have your electrician put a volt meter to the motor under load a match the manufacturers numbers to yours and perhaps the motor has internal problem(s). Best Regards.

Hi sir thanks for that, actually I' m now in 80% to solve the problem.I remove now the twin board as I said but actually I'm wrong thanks a heatsink with a special heat solution to cover the transistors and IC inside.Then I checked now the load transistor and capacitor using analog voltmeter 360 trf.I found out the resistor that have a color code red, red, orange, gold drop to .2ohms with the correct resistance of 22k ohms + - with the tolerance.Then the capacitor I cannot test it because of very small value .01uf and .47uf.Then I check the ball baring of the motor Its nearly loosen inside.I cannot remove the metal cover of the motor because I have no driver for the special screw.